Destruction of fumes and the like



rJune 15, 1937.

A. E. STILSON DESTRUCTION 0F FUMEs AND THE LIKE Filed June l0," 1935 Patented June 15, 1937 UNITED STATES PATENT OFFICE 9 Claims.

This invention relates to the handling of explosive and highly inflammable fumes and, among other objects, aims to facilitate the safe removal of such fumes from their point of generation and their safe destruction.

The invention may be readily understood by reference to one illustrative embodiment thereof described in the following specification and illustrated in the accompanying drawing.

10 In said drawing:

Fig. 1 is an elevation and partly diagrammatic view of apparatus representing a source of explosive or inflammable fumes and the like, associated with which is equipment for safely removing and destroying such fumes, the destructor itself being illustrated in vertical section taken on the plane I-I of Fig. 2; and

Fig. 2 is a transverse sectional elevation of the destructor taken on the plane 2 2 of Fig. 1.

Experience has demonstrated that explosive fumes and those so highly inflammable that they must be included in the same category as explosive fumes, cannot be handled in the same manner as ordinary combustible or obnoxious gases and fumes. While the latter have been satisfactorily disposed of by causing them to pass through a zone of burning flame, efforts so to destroy the former have not only been unsuccessful but dangerous. Indeed, the methods heretofore proposed have demonstrated a failure to appreciate the peculiarities in the problem to be solved.

The present invention deals not only with the danger of explosion but with the high rate of dame propagation of certain mixtures of gases or fumes. I have found that all explosive gases and fumes encountered in industrial processes can be rendered non-explosive, while yet being inflammable, by addition of air thereto; `and can be safely handled and destroyed by transporting them at speeds greater than their rate of flame propagation. The amount of air added depends both upon the particular kind of fume or gas and the amount of inert gases mixed therewith and should be that amount which will render the fumes non-explosive but not non-innammable. Beyond this amount, additional air makes it difficult and uneconomical to destroy the fumes and gases. Nevertheless, destruction is generally necessary because of noxious odors carried with the fumes. In fumes which have been excessively diluted with air, destruction cannot be effected unless every part of the fumes is raised by external heat above the combustion point of the fumes to be destroyed. This involves excessive waste since the admixed air and inert gases must also be raised to this temperature. Furthermore, .the thermal value of the fumes themselves is either Wasted or cannot be effectively utilized.

The inflammable fumes resulting from limited and controlled dilution with air of the explosive fumes, and also the aforesaid highly inflammable fumes, have a high rate of name propagation. To burn and destroy such fumes requires special technique vand special apparatus. The fumes and gases thus diluted are conveyed from their point or po-ints of generation in conduits so designed that at least in one region thereof the gases have a velocity substantially greater than their speed of flame propagation. They may then be safely delivered to an apparatus, such as herein described, where destruction may be effected.

In the illustrative method the apparatus I0 represents kettles or other industrial equipment in the use of which explosive, highly inflammable or obnoxious gases vare generated. These gases are conveyed kaway from their point of generation in conduits II by a centrifugal blower I2 or other appropriate means, such as a properly designed chimney', for producing adequate suction. Air 'is mixed with the gases to dilute them below their explosive point or the point of explosive inflammability, in this instance, by drawing the same through a regulating valve I3 into the conduit under the suction of the blower. From the blower the gases thus diluted are delivered through conduit I4 to the destructor I5 in which the fumes are burned as presently described.V By an inspection of the character of the flame in the Aspace I6 inside the destructor, the rate of introduction of air through lthe valve I3 may be regulated to that amount necessary to prevent explosion. Excess air beyond what is necessary to effect combustion is not desired since it results .in uneconomical operation. The speed of operation of the fan or other suction means is regulated yso that the velocity of fumes and gases through the conduit I4 is in excess of the rate of flame propagation so that during the burning of the fumes inside the destructor, the flame cannot travel in the reverse direction through the conduit I4 and to the kettles I0 or conduits II where explosion might take place.

On entering the space I6 of the destructor, the velocity of `the incoming ,gases is of course very substantially reduced' by reason of the large cross-section of the space in relation to that of the conduit; and in such space the gases encounter burning iames .supplied by some appropriate means such as a gas or oil burner or burners Il' or even an incandescent coal bed. The burners are advantageously designed to produce a flat fan-like fiame across the passage through which the gases must pass on their way to the combustion chambers.

While the combustion of the fumes which thus takes place in the space I6 may be violent, serious results are avoided by sub-atmospheric pressure maintained in the chamber. In the present instance such condition is maintained by the natural or artificial suction of the outlet flue I8 located at the other end of the apparatus. The tendency therefore to develop high pressures which might accelerate the rate of combustion is therefore successfully combated by the subatmospheric pressure thus maintained inside the destructor.

The combustion space I6 is advantageously supplied with bailies lil whichpromote thorough intermingling and combustion of the gases. It should be noted that the combustion space expands or enlarges in section as the gases pass toward the flue. Thus the space, 20 isV larger than the space 2l, space 22 is larger than space 20, and space 23 is larger than space 22. The latter space advantageously contains checkerbrick 24 of low heat conductivity (i, e., consisting of refractory insulating material) which may therefore be raised to incandescence in a minimum length of time. Preferably some brick are omitted in the region 25 adjacent the entrance to the flue to carry out the principle of gradually enlarging the combustion space toward the flue.

Clogging of the checker-brickwork is avoided by the continued combustion which takes place in the checker-brick itself, thus burning away any matter which would otherwise have a tendency to accumulate on the checkerwork. In connection with the operation of the destructor, it should be noted that the internal pressure is gradually reduced (i. e., the suction is increased) as the gases approach the flue I8. This is the natural result of the suction head necessary t0 drive or carry the gases through the destructor and serves also quickly to expand vthe gases on entering the destructor and to break their static velocity. Hence the violently burning fumes will tend always to travel toward the flue and not toward their point of introduction into the destructor.

It will be observed that substantial intermixing of fumes and burning flames is effected not only by the action of the burner flames encountering the entering gases (whose velocity is suddenly reduced) but by the baffles and vcheckerwork through which the gases pass.k 'I'his makes it possible to employ the apparatus for deodorizing (by means of combustion) obnoxious gases which may be so diluted either by air or inert gases as not to be freely burning. The design of the apparatus is such that for a period of approximately one to one and a quarter seconds the gases are subjected to temperatures above their ignition point, thereby insuring complete destruction of obnoxious fumes and odors.

In employing the foregoing method and apparatus to a given explosive gas or fume, it is desirable to ascertain its speed of llame propagation and the amount of air necessary for adequate dilution of the gas or fume. This can easily be determined and with such data it is possible to adjust the apparatus for operation at maximum efficiency.

As here shown, the destructor is lined with refractory brick 26 capable of withstanding any high temperatures which may be developed. The apparatus is also advantageously insulated by an external layer of mineral Wool 2l' or other' appropriate insulation and is jacketed by a steel casing 28. Doors 29 are provided to allow inspection and repair of the interior of the destructor and replacement and repair of the checkerwork.

Obviously the invention is not limited to the details of the illustrative embodiment since these may be variously modified. Moreover, it is not indispensable that all features of the invention beused conjointly since various features may be used to advantage in different combinations and subcombinations.

Having described my invention, I claim:

1. The method of destroying explosive or highly inflammable gases and fumes which is characterized by mixing the same with such proportion of air as will reduce the inflammability of the gases without rendering them non-inflammable, transporting the same to a point of combustion and there destroying the same through combustion, moving the mixed gases through a portion of their travel to the point of combustion l# at a speed exceeding the rate of flame propagation in such gases thereby to prevent propagation of flame to the point of generation of said gases or fumes.

2. The method of destroying explosive or v highly inflammable gases and fumes which is characterized by diluting the same with air and transporting them from the point of generation and introducing the same into an enlarg-ed enclosed combustion to flame, a portion place at a speed propagation thereby to prevent propagation of flame to the point of generation of said gases or fumes, and applying suction to said combustion space to cause the gases to expand in their passage through said combustion space.

3. The method of destroying explosive or highly inflammable gases and fumes which is characterized by transporting them fromv the point of generation and introducing the same into an enlarged combustion space which increases in section from the point of entrance to allow the gases to expand of said transportation taking gases to flame in said combustion space, a porspace and then exposing them I exceeding the rate of ame` diluting the same with air and ,Y

tion of said transportation taking place at a I speed exceeding the rate of ame propagation thereby to prevent propagation of flame to the point of generation applying suction to the exit end of said chamber, whereby the gases are caused to expand continuously in their passagethrough the chamber.

4. Apparatus for destroying explosive or highly inflammable fumes or gases comprising in combination a destructor chamber having a combustion space of enlarging section fromfits entrance to its exit, an inlet conduit for conveying the said gases or fumes to the chamber inlet and having means for effecting a controlled dilution of the gases or fumes with air prior to their introduction into the chamber, and means for causing the gases o-r fumes tol travel in a portion of said conduit at a speed greater than the rate of flame propagation in the gases, thereby preventing access of dame to the gases or fumes vhile in explosive or highly inflammable condiion.

5. The method of destroying explosive or highof said gases or fumes, and

ly inflammable gases and fumes which is characterzed by transporting the same from their point of generation and during such transporting mixing the same with a limited amount of air to produce gases Whi-ch will burn without explosive violence and producing a gas Velocity in excess of thespeed of flame propagation of the gases, delivering the diluted gases to a combustion space and burning the same in such space.

6. Apparatus of the character described comprising in combination a. source of generation of explosive or highly inflammable fumes or gases, a destructor chamber having adjacent its inlet end a source of heat, a conduit leading from said source of generation to said destructor chamber for conveying said gases to the latter, means located in advance of said chamber and associated With said conduit for producing a gas velocity therein in excess of the rate of flame propagation, thereby preventing access of the flame in said chamber to said gases Whilein explosive or highly inflammable condition, means in said conduit for diluting the -gases or fumes With a limited amount of air prior to their introduction into the chamber to render them less inflammable but not non-inflammable.

7. Apparatus of the character described comprising in combination a source of generation of explosive or highly inflammable fumes or gases, a destructor chamber, a conduit leading from said source of generation to said destructor chamber for conveying said gases thereto, means associated with said conduit for creating a gas velocity in a portion of said conduit greater than the speed of flame propagation, said conduit having means for diluting the gases or fumes with a limited amount of air prior to their introduction into the chamber to render them less inflammable but not non-inflammable, said charnber having adjacent its inlet end a source of heat and having transversely extending baiiles for effecting a mixture of the burnin-g gases as they pass through said chamber.

8. Apparatus of the character described cornprising in combination a source of generation of explosive or highly inflammable fumes or gases, a destructor chamber having adjacent its inlet end a source of heat, an inlet conduit leading from said source of generation to said destructor chamber for conveying said gases thereto, means for applying suction to said destructor chamber to cause the gases therein to expand progressively as they pass through the chamber, means in advance of said chamber for causing a gas velocity in a portion of said conduit in excess of the speed of flame propagation, and means for diluting said gases or fumes with a limited amount of air prior to their introduction into the chamber to render them less inflammable but not non-inflammable.

9. Apparatus of the character described comprising in combination a source of generation of explosive or highly inammable fumes or gases, a destructor chamber having adjacent its inlet end a source of heat, an inlet conduit leading from said source of generation to said destructor chamber for conveying said gases thereto, means for causing the gases to expand progressively as they pass through said chamber, means in advance of said chamber for causing a gas velocity in a portion of said conduit in excess of the speed of flame propagation, and means for diluting said gases or fumes With a limited amount of air prior to their introduction into the charnber to render them less inflammable but not noninflammable.

ALDEN E. STILSO-N. 

